Kiwi plant named ‘AU Gulf Coast Gold’

ABSTRACT

‘AU Gulf Coast Gold’ is a new golden-fleshed cultivar of Actinidia chinensis Planch with a low chilling requirement. ‘AU Gulf Coast Gold’ fruit is large, cylindrical and uniform in shape with yellow flesh that has a thick sweet flavor and delicious taste. ‘AU Gulf Coast Gold’ fruit has a high percent soluble solids and dry matter content. Vegetative bud burst begins in late March to early April and flowering begins on average April 18-20 in central Alabama. Fruit typically reaches maturity September 21-25 in central Alabama with an internal color hue of less than 103°.

Latin name of the genus and species of the plant claimed: Actinidia chinensis Planch.

Variety denomination: ‘AU GULF COAST GOLD’.

BACKGROUND OF THE INVENTION

The genus Actinidia is native to China and is comprised of more than 50 species. Actinidia chinensis Planch and Actinidia deliciosa (A. Chev). C.F. Liang and A.R. Ferguson are the two most important commercial Actinidia species. Actinidia chinensis is more precocious and productive and the fruit are more attractive in appearance with less pubescence on the fruit skin than A. deliciosa.

Kiwifruit plants are dioecious and have vegetative and compound buds with flower clusters produced in the leaf axils of the first four to six nodes of shoots arising from buds on one year old shoots. Male and female flowers are perfect morphologically. The female flower contains some anthers, but only the stigma is functional, whereas the flower on a male vine typically produces 125-185 large anthers that surround a small vestigial stigma. For pollination and fruit set to occur, the female plant must be in close proximity of a male plant whose bloom period occurs at the same time as the female plant's bloom period.

‘AU Gulf Coast Gold’ is a new golden-fleshed cultivar of Actinidia chinensis Planch. It is a bud mutation that occurred on a ‘AU Golden Sunshine’ (U.S. Plant Pat. No. 22,159) plant in a cultivated and maintained orchard to evaluate kiwifruit cultivar performance at Fairhope, Baldwin County, Ala. Based on the genetic marker comparison of ‘AU Golden Sunshine’ (patented) and ‘AU Gulf Coast Gold’, the genetic distinction between these two cultivars is strong (Table 1). Wood from this plant was grafted onto Actinidia deliciosa kiwifruit plants at Clanton, Chilton County, Ala., where it has been grown and evaluated since 1999. ‘AU Gulf Coast Gold’ has been asexually reproduced at Auburn, Clanton and Reeltown, Ala. and Marysville and Reedly, Calif., USA by rooting softwood and hardwood cuttings, by whip and cleft grafting and tissue culture. Genetics have been stable through succeeding asexual propagation.

‘AU Gulf Coast Gold’ fruit is large, cylindrical and uniform in shape with golden flesh that has a thick sweet flavor and delicious taste. ‘AU Gulf Coast Gold’ fruit has high percent soluble solids and dry matter typically higher than ‘AU Golden Sunshine’ (patented) and comparable to slightly lower than ‘Hort 16A’ A. chinensis (U.S. Plant Pat. No. 11,066) (Table 2). Dry matter content, a positively correlated indicator of soluble solids content of kiwifruit when allowed to ripen, appears to be closely related to fruit development period, and ‘AU Gulf Coast Gold’ has a longer fruit development period compared to ‘AU Golden Sunshine’ (patented) and a shorter fruit development period compared to ‘Hort 16A’ (patented). Increasing dry matter content has been shown to increase purchase likelihood for kiwifruit (Jaeger et al., 2011). ‘AU Gulf Coast Gold’ bloom period begins 1-2 days before ‘AU Golden Sunshine’ (patented), and is completed 2 days before ‘AU Golden Sunshine’ (patented) bloom period (Table 3).

SUMMARY OF THE INVENTION

The present invention relates to a new and distinct early to mid season ripening yellow fleshed kiwifruit cultivar that produces cylindrical, uniformly shaped fruit with the stylar end rounded to somewhat pointed, and the shape on the stalk end rounded and narrow. Fruit skin color is grey brown (N199B) color with medium density of uniform short lanulose hairs on fruit skin surface (Table 4). At maturity, the fruit surface appears brown due to the lanulose hairs.

The new cultivar is able to be asexually reproduced by softwood and hardwood cuttings or by grafting onto a rootstock. The unique characteristics come true to form and are established and transmitted through succeeding asexual propagations. ‘AU Gulf Coast Gold’ has been asexually propagated by rooting softwood and hardwood cuttings, and by whip and cleft grafting in Alabama and California, USA.

Kiwifruit plants are dioecious and have vegetative and compound buds with flower clusters produced in the leaf axils of the first four to six nodes. Male and female flowers are perfect morphologically. The female flower contains some anthers but only the stigma is functional whereas the flower on a male vine typically produces 125 to 185 large anthers that surround a small, vestigial stigma. In Alabama, ‘AU Golden Tiger’ (U.S. Plant Pat. No. 22,140) and ‘Chieftain’ (unpatented) are the male cultivars used as pollinizers. ‘AU Golden Tiger’ (patented) bloom period begins with ‘AU Gulf Coast Gold’, and ‘Chieftain’ bloom period begins during the latter part of ‘AU Gulf Coast Gold’ bloom period.

Kiwifruit buds enter endodormancy during winter, which requires a minimum number of chilling hours for maximum budbreak and bloom. Floral uniformity and density in spring is directly related to the amount of chilling received during winter. It is believed the more accurate measure of chilling hours is Richardson units, which are defined as the accumulated hours between 0° C. and 7° C.

For maximum bud break and flowering of ‘AU Golden Sunshine’ (patented) to occur it was determined that 700 hours of chilling was required and after the chilling requirements was met 15000 growing degree hours were necessary for bud break (Wall et al. 2008). ‘AU Gulf Coast Gold’ has similar chilling requirement as ‘AU Golden Sunshine’ (patented). The high growing degree hours requirement results in a late bud break and blooming period that typically occurs after the danger of a late spring frost. ‘AU Gulf Coast Gold’ has performed well in central Alabama where it receives an average winter chilling of 800-1200 hours.

In central Alabama, ‘AU Gulf Coast Gold’ flowers begin to open ˜2 days before ‘AU Golden Sunshine’ (patented) and its fruit ripens several weeks after ‘AU Golden Sunshine’ in the fall. ‘AU Gulf Coast Gold’ reaches harvest maturity 21-30 days after ‘AU Golden Sunshine’ (patented) (Table 2). ‘AU Gulf Coast Gold’ has a cylindrical fruit shape, as does ‘AU Golden Sunshine’ (patented). However, the stylar end is rounded to somewhat pointed in comparison to the rounded stylar end of ‘AU Golden Sunshine’ (patented). The shape of the shoulder on the stalk end of ‘AU Gulf Coast Gold’ is rounded and narrow in comparison to the rounded to flat shoulder on the stalk end of ‘AU Golden Sunshine’ (patented).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph of ‘AU Golden Sunshine’ (patented) fruit (on left) and ‘AU Gulf Coast Gold’ fruit (on right).

FIG. 2 is a photograph of ‘AU Gulf Coast Gold’ fruit cut in half lengthwise and widthwise to illustrate flesh color.

FIG. 3 is a photograph of ‘AU Gulf Coast Gold’ flowers and flower buds on a 16-year old grafted plant.

FIG. 4 is photograph of ‘AU Gulf Coast Gold’ flower bud density on 16-year old grafted plant.

FIG. 5 is a photograph of ‘AU Gulf Coast Gold’ flowers at different stages of development to illustrate flower bud density on a 16-year old grafted plant.

FIG. 6 is a photograph of ‘AU Gulf Coast Gold’ fruit on 16-year old grafted plant.

FIG. 7 is a photograph of ‘AU Gulf Coast Gold’ fruit load on vine on a 14-year old grafted plant.

FIG. 8 is a photograph of ‘AU Gulf Coast Gold’ fruit on 16-year old grafted plant.

DETAILED BOTANICAL DESCRIPTION

Kiwifruit plants are large deciduous shrubs that originated in China and are dioecious, can climb up to 25 feet, and have alternated, broadly rounded petiolate leaves. The cream-colored flowers that grow in axillary cymes mature into ovate to oblong fruits (berries) with brownish, hairy skins. There are over 50 species in the genus Actinidia. The two Actinidia species of the most commercial importance are deliciosa and chinensis. The kiwifruit plant is dioecious thereby requiring male pollenizers in the presence of the female plants to ensure fruit production. The male and female plants bloom period has to be at the same time for pollination to occur. The bloom period varies with each cultivar depending upon the chilling requirement and the growing degree hour requirement after the chilling requirement has been met. Actinidia are temperate zone plants that prefer well-drained moist and rich soil and grows well in full sun or part-shade.

The new cultivar ‘AU Gulf Coast Gold’ is pistillate, with imperfect flowers, e.g. the flowers produce only sterile pollen and thus require a pollenizer for fruit production. The male cultivars ‘AU Tiger’ (patented) and ‘Chieftain’ (unpatented) are pollenizers used with ‘AU Gulf Coast Gold’. The bloom period of ‘AU Gulf Coast Gold’ starts about April 18^(th) in central Alabama, typically ˜2 days before the ‘AU Golden Sunshine’ (patented) bloom period.

The new cultivar can be asexually reproduced by softwood and hardwood cuttings or by grafting onto a seedling or cutting grown rootstock. The unique characteristics come true to form and are established and transmitted through succeeding asexual propagations.

‘AU Gulf Coast Gold’ is a bud mutation that occurred on a ‘AU Golden Sunshine’ (U.S. Plant Pat. No. 22,159) plant in a kiwifruit cultivar evaluation planting at Fairhope, Baldwin County, Ala. Based on the genetic marker comparison of ‘AU Golden Sunshine’ (patented) and ‘AU Gulf Coast Gold’, the genetic distinction between these two cultivars is strong (Table 1).

TABLE 1 Genetic marker comparison of ‘AU Golden Sunshine’ (patented) and ‘AU Gulf Coast Gold’^(z). Variety 554^(y) 559^(x) 565^(w) 566^(v) AU Golden 142,152 ^(u), 131, 163 95,107 84,86,88,102 Sunshine 162, 164 AU Gulf Coast 150,152, 131, 163,172 88,93,95,98 84,88,92,100 Gold 162, 164 ^(z)DNA was extracted from leaf tissue. PCR was performed by using 4 SSR (microsatellite) markers. Capillary electrophoresis was performed using ABI3100 Genetic Analyzer. Data was analyzed using GeneScan and Genotyper. ^(y)Marker 554 - UDK96-026 ^(x)Marker 559 - UDK96-037 ^(w)Marker 565 - UDK97-406 ^(v)Marker 407 - UDK97407 ^(u)Common alleles in bold type for both varieties.

‘AU Gulf Coast Gold’ fruit has high percent soluble solids and dry matter typically higher than ‘AU Golden Sunshine’ (patented) and comparable to slightly lower than ‘Hort 16A’ A. chinensis (U.S. Plant Pat. No. 11,066) (Table 2).

TABLE 2 Harvest date^(z) and fruit quality^(y) attributes at harvest of three Actinidia chinensis Planch. var. chinensis cultivars grown in central Alabama. 2014 2015 Soluble Dry Internal Harvest Harvest Firmness Solids Matter Color Cultivar Date Date (kg) (%) (%) (hue°) ‘AU Golden Sept. 4 Aug. 25 5.5 ± 1.8 8.2 ± 17.9 ± 103.1 ± Sunshine’ 2.3 0.012 2.5 ‘AU Gulf Sept. 25 Sept. 21 4.6 ± 0.9 8.4 ± 21.2 ± 102.9 ± Coast Gold’ 0.8 0.007 2.7 ‘HORT 16A’ Oct. 9 Oct. 19 5.2 ± 1.0 12.9 ± 22.2 ± 103.6 ± 3.0 0.007 2.9 ^(z)Harvest date for each cultivar was based primarily on an internal color of <104 hue°. ^(y)Means derived from 10 fruit/year at specified harvest date.

‘AU Gulf Coast Gold’ bloom period begins 1-2 days before ‘AU Golden Sunshine’ (patented), and is completed 2 days before ‘AU Golden Sunshine’ (patented) bloom period (Table 3).

TABLE 3 Flower development of ‘AU Golden Sunshine’ (patented) and ‘AU Gulf Coast Gold’ in 2009, 2010, and 2016. 2009 Cultivar Apr. 17 Apr. 20 Apr. 24 Apr. 27 Apr. 29 May 1 AU Golden Bud Popcorn 10-30% Full 10-40% Petal Sunshine swell Stage Bloom Bloom Petal Fall Fall AU Gulf Buds Popcorn 20-50% Full 60-80% Petal Coast Gold Cracking Stage Bloom Bloom Petal Fall Fall 2010 Apr. 21 Apr. 23 Apr. 26 Apr. 28 Apr. 30 May 3 AU Golden Bud Popcorn 80% 90% Full Petal Sunshine swell Stage Bloom Bloom Bloom Fall AU Gulf Popcorn 50% 70-100% Full Some Petal Coast Gold Stage Bloom Bloom Bloom Petal Fall Fall 2016 Apr. 17 Apr. 21 Apr. 25 Apr. 27 AU Golden Popcorn 30-40% 80% Bloom Petal Fall Sunshine Stage Bloom AU Gulf 10-% 40-50% Full Bloom Petal Fall Coast Gold Bloom Bloom

The average plant height and spread for ‘Au Gulf Coast Gold’ was limited by pruning the plants and training them to a limited space of 8′×16′ on top of trellis. The remaining botanical information is provided below in Table 4.

TABLE 4 Botanical description of ‘AU Gulf Coast Gold’ and comparison to ‘AU Golden Sunshine’ ‘Gulf Coast Gold’ ‘Golden Sunshine’ PLANT Plant hardiness Has performed well in zones 8A & 8B Plant: sex expression female (flower imperfect) Plant: ploidy diploid (2n = 2x = 58) Plant: vigor strong Young shoot: hairs present Young shoot: density medium of hairs Young shoot: type of hairs short Young shoot: anthocyanin absent (stem color - coloration of growing tip 152B) Young shoot: anthocyanin absent (stem color - coloration of leaf axil 152B) Insect pest susceptibility White peach scale (Pseudaulacas pispentagona Targioni) leaffooted bug (Leptoglossus phyllopus Linnaeus) Diseases None observed STEM Stem: coloration of Grey-brown, N199A leaf axil Stem: diameter medium Stem base diamenter mean 12.9 mm (range 9.5-18.3 mm) [20] Stem mid section mean 9.9 mm (range 7.4- diameter (range 7.3-12.7) [20] 12.5 mm) Stem: dormant bud 4.3 mm (2.4-6.0) [20] 4.2 mm (2.5-6.1) diameter Stem: color on upper side Grey-brown (N199B) grey-brown of shoot (N199A) Stem: character of bark smooth Stem: hairs few Stem: conspicuous- weak ness of lenticels Stem: number of lenticels few Stem: color of lenticels greyed-orange (N-167A) brownish-white Stem: size of bud support large Stem: visibility of bud visible (dormant canes) Stern: number of hairs high visible on bud (dormant canes) Stem: leaf scar mean length 6.1 mm mean length 5.5 (5.8-7.2 mm) mm (4.7-5.9 mm) mean width 5.6 mm mean width 5.7 (5-6.5 mm) mm (5-6.3 mm) LEAF (Mature) Leaf shape: orbicular to broadly broadly cordate ovate: as broad as to orbicular long, occasionally broader than long Leaf base shape: round to cordate, with rounded to cordate; lobes touching to lobes not occasionally over- overlapping lapping; rarely broadly Leaf tip shape: rounded, usually with broadly obtuse acute to acuminate tip, with cuspidate rarely with 3 broad, tip shallow lobes Leaf margin: entire Leaf adaxial surface: yellow green, dull medium to dark (147A); glabrous green (147A); except for minute glabrous except hairs along midvein for sparse un- branched hairs along veins Leaf abaxial surface: yellow green (147B); light green (147B); densely stellate pub- dense, stellate escent except on mid- pubescence every- vein which has minute, where except along reddish-brown, crinkled main veins non-branching hairs which are densely tomentose tomentose with unbranched hairs Leaf length (cm): 22.6 (18.0-28.5) [20] 20.1 (16.8-24.1) Leaf width (cm): 12.7 (10.2-17.5) [20] 15.3 (13.1-18.2) Leaf ratio (l/w): 1.8 (1.3-2.5) [20] 1.3 (1.2-1.5) Leaf petiole length (cm): 10.7 (6.6-15.4) [20] 6.4 (5-8.7) Leaf 1° vein organization: pinnate; veins pinnate; veins terminating as a small terminating as points extended beyond small extended the blade (minutely points or mucros apiculate), to 1.2 mm at leaf margins in length Leaf 2° vein organization: ± parallel Leaf puckering: medium weak Leaf variegation none Leaf spines on lower leaf none Leaf surface none Leaf petiole none Young shoot hairs present Young shoot::density medium of hairs Young shoot::type short of hairs Young shoot::antho- absent cyanin color FLOWER Inflorescence type dichasium Inflorescence #: mean 1.6 (range 1-3) mean 2.2 [20] (range 1-3) [32] 1° Pedicel length (cm): mean 2.8 3.7(2.5-4.6) [16] (range 1.8-3.9) [20] 2° Pedicel length (cm): mean 1.5 1.8 (1.4-2.1) [14] (range 1.2-2.1) [20] Pedicel pubescence: minutely short, dense, minutely, densely unbranched tomentose; Sepal #: mean 6.1 unbranched 5.7 (range 5.0-7.0) [20] (5-8) [26] Sepal color: yellow green (147A) gray-green to to greyed orange slightly rust- (166C) along margin colored at margins Sepal pubescence: dense, minutely minutely, densely tomentose with rusty tomentose, brown crinkled hairs unbranched Flower per infloresence mean 3.4 (range 3-5) [20] Flower color: creamy white (155D) Flower width (cm): mean 4.2 (range 1.6-4.8) 5.0 (4.8-5.8) [14] Petal orientation: overlapping distinct to overlapping Petal # mean 6.2 6.4 (5-9) [17] (range 5.0-8.0) [20] Petal length (cm): mean 2.0 2.1 (1.7-2.5) [2] (range 1.8-2.4) [20] Petal width (cm): mean 1.7 1.6 (1.4-2.1) [20] (range 1.3-2.0) [20] Petal ratio (l/w): mean 1.2 1.3 (1.0-1.6)[20] (range 1.0-1.4) [20] Ovary shape: globose Ovary pubescence: white, densely lanose, minutely, densely thicker toward apex pilose; unbranched Style #: mean 24.4 20 (17-22) (range 19-31)[20] Style orientation: spreading to upright upright to spreading Stamen #: mean 40.9 85.4 (80-96) (range 36-49) [20] Anther length (mm): mean 3.3 3.0-4.0 (range 2.5-3.6) [20] Chilling requirement hrs: 700 FRUIT Fruit: average size (g) 96.8 90.4 (47.7-149.6) (47.9-147.0 Fruit: length (mm) 71.5 66.8 (52.1-82.0) (51.9-80.3) Fruit: width (max) (mm) 48.3 48.4 (38.4-62.8) Fruit: L/A ratio 1.48 1.38 (max width) Fruit: width (min) (mm) 45.1 44.7 (34.2-50.1) (37.3-51.8) Fruit: LID ratio 1.59 1.49 (min width) Fruit: core diameter 14.1 14.3 (max) (mm) (3.1-20.5) (3.2-21.7) Fruit: core diameter 5.1 5.6 (max) (mm) (2.3-11.5) (2.7-12.7) Fruit: locule number 36.1 36.8 (30-40) (31-40) Fruit: peduncle length 27.1 28.7 (mm) (19.7-31.7) (21.6-34.2) Fruit: peduncle 2.32 1.7 width (mm) (1.8-2.7) (1.2-2.6) Fruit: general shape cylindrical Fruit: cross-section at round to rarely slightly round median compressed Fruit: general shape of rounded to somewhat rounded stylar end pointed Fruit: shape of shoulder rounded, narrow rounded, flat on stalk end Fruit: skin color at grey-brown dark side brown harvest N199B, light side N199D Fruit: skin color change grey-brown, dark side absent during ripening N199B, light side N199D Fruit: skin color at grey-brown (N199A) brown maturity for consumption Fruit: hairs present Fruit: density of hairs medium light Fruit: type of hairs lanulose (minutely tomentose wooly) Fruit: hair length (mm) short (to 1.0 mm) short (0.05-0.15) Fruit: concentration uniform to slightly con- uniform of hairs centrated distally Fruit: adherence of hairs strong weak to skin (when rubbed) Fruit: core diameter 10 mm (short diameter = large (10.0 mm by (at largest diameter) 4.5 mm) 3.4 mm) Fruit core shape (in round to elliptical elliptical cross-section) Fruit: core woody spike present Fruit: prominence of core medium woody spike Fruit: outer pericarp yellow green (153C) yellow-green color at maturity for (152C-152D) consumption Fruit: inner pericarp color yellow green yellow-green (locules) at maturity for (153C to 153D) (148A) consumption Fruit: core color at greyed yellow (160C) maturity Fruit: seed color at N200A, dark brown brown (165C) maturity in flesh Fruit: seed color when dry greyed orange 165A Fruit sweetness high Fruit acidity medium Storage: successfully stored for 4 months at 33° F. Color Chart RHS Colour Chart: The Royal Horticulture Society, London 2001 Outer Pericarp 153C Inner Pericarp 153D Fruit Core at Harvest 160C Seed Color (in flesh) 200A Seed Color (dry seed) 165A Fruit skin at maturity N199A Leaf Color: Mature leaf after petal fall Upper side of leaf 147A Lower side of leaf 147B Flower petals: Main body of petal 155D Plant stem: Exposed side N199A

Notes regarding Table 4:

1. Horticulture terminology is used in accordance with revised UPOV guidelines for kiwi.

2. Characters of comparison cultivar ‘AU Golden Sunshine’ are noted opposite that character when significantly different.

3. ‘AU Golden Sunshine’ plants were observed in the same experimental planting as the new cultivar.

4. All dimensions are in millimeters unless otherwise stated; weights are in grams.

5. The R.H.S. 2001 Color Chart used to determine actual color.

6. The numbers in brackets, e.g., after any reported number is the number of total measurements made. The number in parentheses e.g., ( ) is the range of the measurement.

LITERATURE CITED

Huang, H., S. Wang, Z. Zhang, and J. Gong. 2003. Exploration of Actinidia genetic resources and development of kiwifruit industry in China. Acta Hort 610:29-43.

Jaeger, S. R., R. Harker, C. M. Triggs, A. Gunson, R. L. Campbell, R. Jackman and C. Requejo-Jackman. 2011. Determining consumer purchase intentions: The importance of dry matter, size and price of kiwifruit. J. Food Sci. 76(3):177-184.

Jiang, Z., S. Wang, R. Huang, Z. Zhang, and H. Huang. 2005. ‘Wuzhi No3’ kiwifruit. HortScience 40(6):1923-1924.

Patterson, K., J. Burdon and N. Lallu. 2003. ‘Hort 16A’ kiwifruit: Progress and issues with commercialization. Acta Hort. 610:267-273.

Ramnoguilhem, M. And J. L. Tailleur. 2005. Kiwi, p. 185-207. In: J. M. Lespinasse and E. Leterme (eds.). Growing Fruit Trees. W.W. Norton & Company, New York, USA.

Sale, P. R. 1983. Kiwifruit culture. Govt. Printing Office, Wellington, New Zealand. pp. 95.

Wall, C., W. A. Dozier, Jr., R. C. Ebel, B. S. Wilkins, F. M. Woods, and W. G. Foshee III. 2008. Vegetative and floral chilling requirements of four new kiwi cultivars of Actinidia chinensis and A. deliciosa. HortScience 43(3):644-647.

Wang, M. Y., E. MacRae, M. Wohlers and K. Marsh. 2011. Changes in volatile production and sensory quality of kiwifruit during fruit maturation in Actinidia deliciosa ‘Hayward’ and A. chinensis ‘Hort 16A’. Postharvest Biol. and Technol. 59:16-24. 

We claim:
 1. A new and distinct variety of Actinidia chinensis Planch plant named ‘AU Gulf Coast Gold’ substantially as described and illustrated herein. 